Metering pin



the usual manner.

Patented Apr. 1, 1952 UNITED STATES PATENT OFFICE METERING PINApplication February 12, 1947, Serial No. 727,962

1 Claim. 1

This invention relates in general to fuel mixing devices or carburetors,and has particular reference to improvements in the construction andoperative assembly of a fuel metering valve for controlling fueldelivery to the carburetor mixing passage.

In a metering valve device of the character providing a metering jet anda control rod or valve having a tapered or stepped control portionoperative through the jet orifice, it has been found that the amount offuel drawn through the orifice in response to a given suction, will varyupon variations in the position of the metering rod with respect to thecenter of the jet orifice. On the other hand, the fuel flow will remainsubstantially constant for a given suction, so long as the. -1neteringrod is maintained stably in a definite position in the orifice. PatentNo. 1,961,747, issued to William M. Ewart discloses a light springconstantly biasing the rod against a side of the orifice for thispurpose. This patent also shows the metering rod attached to anoperating lever by a separate pivot pin projected through an eye in therod, with a retainer key, in Where the metering rod is carried by avertically disposed, flexible diaphragm, mounted in a wall of the fuelbowl as shown, for instance, in Bicknell Patent No. 2,408,726 andCarlson et a1. Patent No. 2,407,535, the mounting and assembling problemis complicated by the cantilever support and concealed positioning ofthe rod. For these reasons, the rod attachments in the above patentshave not proven Wholly satisfactory.

The principal object of the present invention is to provide simplified,yet effective means for attaching a metering rod to an actuating member,such as adiaphragm.

Another object is to provide a metering rod mounting which eliminatesthe use of separate assembly elements such as pivot pins, cotters andthe like.

Still another object is to provide novel means to maintain the meteringrod stably positioned in the jet orifice.

Other objects and advantages of the present invention as a whole and inrespect to certain features thereof, will appear readily from thefollowing description and accompanying drawing.

In the drawing:

Fig. l is a verticalelevation of a carburetor with parts thereof shownin section to illustrate the invention as applied thereto;

Fig. 12 is an enlarged detail view in side elevation, of a metering rodand rod operating memher in assembly according to one embodiment of theinvention, part of the operating member alppearing in section;

Fig. 3 is a plan view of the rod assembly "according to Fig. 2;

Fig. 4 is an enlarged detail side view and section of a modified form ofmetering rod and operating member assembly;

Fig. 5 is a View similar to Figs. 2 and 4, but showing anothermodification.

The present invention is Ishown applied It-O a metering valve device ofan automatically operated type, wherein the longitudinal controlposition of the metering rod is determined :by a suction operateddiaphragm responsive to pressure conditions in the engine manifoldHowever, the same may be applied with equal facility, to metering valvearrangements of other types, as one wherein the metering element issubject to direct control by the throttle valve through an operativeconnection therewith.

Illustrated in Fig. '1 is a carburetor designated generally by thenumeral I'D, which may .be of a conventional downdraft type providing aflange l l at its lower end, for attachment to the manifold of aninternal combustion engine (not shown). The carburetor structureincludes a float chamber I? in which fuel is maintained atadesiredlevel, as by a conventionalfioat-valve (not shown). Fuel is suppliedfrom chamber t2 to the carburetor main nozzle (not shown) through arestricted orifice M .in a jet element l5 preferably located in a loweror bottom zone of the supply chamber, and thence through delivery ductsor passages including a horizontal passage I6 adjacent the jet, anupwardly extending passage !l and passage 18. The idling and lowspeedfuel supply is furnished through jet [5, tube [9, and duets 20 and 2|leading to the usual idling port or ports (not shown). Duct 2| isprovided with a flow controlling restriction 21a.

Acceleration fuel is supplied to an :auxiliary nozzle 210 in thecarburetor mixing passage 211, by a pump device including diaphragm M2.The pump draws fuel from the float chamber .1 2 through port 2M, pastcheck valve '2l'5 into pump chamber 2 I 6, and expels'i't past checkvalve 2H3 in the pump delivery passage 219 and auxiliary nozzle 2). Thepump may be operated "by a leverage connection to throttle 33, as in theabove mentioned Bioknell patent.

Controlling fuel flow through J'et orifice I4 is a metering rod 22having its extremity projecting through the jet orifice. 'Theirodcontrol end is of differential or stepped form,- pro'viding a smalldiameter control step 23, an intermediate preferably tapering step 24,and a large diameter step 26. One or another of the metering stepsisdisposed in fuel metering cooperation with the jet orifice, bylongitudinal displacement of the rod.

The metering rod is controlled by a suction device 21 which includes acasing 28 securing in position a flexible diaphragm 36, to provide asuction chamber 3| and pressure chamber 32 communicating with the floatchamber through an opening 34. A passage 35 shown in phantom lines,connects the suction chamber 3i with the carburetor fuel passage 2 Hposterior to the throttle valve 33 therein, so that chamber 3! issubject at all times, to the suction conditions in the engine manifold.Centrally secured to and extending through diaphragm 36 is a plungerguide 36 having a portion 31 slidably received in casing bore 38, theforward end 40 of the plunger mounting by press fit a metering rodattachment member 41. Member ll is operatively connected with themetering rod 22 in a novel manner presently to be described. Completingthe suction device assembly is a suitable compression spring 44 bearingbetween the casing and the cup 55 secured with the diaphragm, the springserving to bias the diaphragm assembly toward the discharged positionshown in Fig. 1 in opposition to engine suction.

With particular reference now to Figs. 2 and 3 which illustrate oneembodiment of the present invention, the metering rod actuating member Mis formed to provide a generally rectangular lug 46 extending forwardlyfrom the forward face 48 of the member rod having a central circularaperture 49. The end section 50 of the metering rod 22 is given asomewhat flattened S or crank shape as shown, providing the portion 52turned laterally from the rod at. a predetermined forward inclination,and the end terminal portion 53 extending forwardly from the portion 52.The diameter of lug opening 49 is greater by a predetermined extent,than the diameter of the rod at its crank end, so as to facilitate readyinsertion of the crank end through the opening during assembly, and toposition the rod crank end such that the crank portion 52 extendsdiagonally through the opening 49. Moreover, the size of the opening 49and the angular relationship and dimensioning of the crank portions withrespect to the diameter of the opening 49 and the thick ness of the lug,are all preselected such that in the assembly, the portion 56 of the rodwill be in supported contact with the lug at but two relatively spacedpoints. As is evident in Fig. 2, the first elbow-bend d of the rodcrank, exposed on the face 56 of the lug, has the crook-point 5'! 7thereof bearing against the underlying corner 58 of lug opening 46,while the second or terminal elbow-bend 66 of the crank, exposed on theopposite face 6! of the lug, has the crook-point 62 thereof in contactwith the underlying corner 64 diagonally opposite to the corner 58. Inconsequence thereof, the metering rod 22 in free projection forwardlyfrom the crank connection to the lug 46, will be in canted relation tothe lug, and the axis 65 of the diaphragm as illustrated in solid linesin Fig. 2.

- Referring again to Fig. 1, the suction device 21 is arranged on thecarburetor with respect to the jet l5, so that in assembly the axes ofthe diaphragm and the jet are coextensive. Accordingly, it is necessaryto deflect the metering rod laterallyin order to permit final assemblyof the suction device to the carburetor, with the metering rod extendinginto the jet orifice and the passage l6. The metering rod therefor isformed from a suitable material, as bar stock, providing a desireddegree of resiliency permitting tensioning of the rod by lateraldeflection thereof. Consequently, the final assembly of the meteringvalve and its suction actuator, the metering rod will be under a lateraltension sufiicient to maintain the control end thereof stably in contactwith one side of the orifices I5, as illustrated by Fig. 1. It is to benoted additionally, that the crank end of the'metering rod is relativelyfree to turn or pivot in the lug opening 49, which thus facilitatesself-adjustment of the rod to the jet.

From the foregoing with respect to the embodiment of the invention asillustrated by Figs. 1, 2 and 3, it will be now fully appreciated thatthe arrangement as described alfords a novel, simple and positivesupporting connection of the meter ing rod to its operating member,which is effected in a direct manner without requirement of separateconnecting elements such as pivot pins, cotters and the like. Further,the arrangement including the two-point operative supporter the meteringrod crank end on the lug of the operating member, results in anoperative positioning of the metering rod through the jet orifice, withthe rod maintained in contact with one side of the orifice solely by thetensioned condition of the rod in its laterally deflected assemblyposition. Thus is obviated any necessity for a spring or otherwiseseparate biasing device, in order to hold the rod against one side ofthe orifice.

A modification of the embodiment of Fig. 2 is shown in Fig. 4, whereincorresponding parts are given the same reference numeralsdiiferentiated, however, by the letter sumx a--. As there shown, the lugopening 49a is directed at an angle through the lug Mia, While the rodcrank portion 52a is directed laterally of the rod so that its axis issubstantially normal to the rod axis, and the crank terminal portion 53ahas its axis substantially parallel with the rod axis. Similarly to theembodiment of Fig. 2, the size of the opening 49a and its inclination,together with the dimensions of the rod crank end 520, are selected sothat in the assembly the crank will bear at its crook-point 51a, on themargin 58a of the lug opening, and at its crook-point 62a, on thediagonally opposite opening margin 64a. Consequently, the rod 22anormally projects at an inclination to the plane of the lug face 56a,representedin edge view by the broken line 65a and is distorted inassembly with the jet. In all other respects, this embodiment is thesame as that of Fig. 2, so that further description thereof is deemedunnecessary.

Fig. 5 illustrates afurther embodiment of the invention, wherein theoperating member 16 which is similar in general to the member 4| (Fig.2) provides an aperture H in the lug 12 thereof, receiving the crank end14 of the metering rod 15 in relatively free or unconstrained extensiontherethrough. Like the first described embodiments, this affords asimple yet positive operative connection of the metering rod and itsactuating member, with one element of the two-part connection providedby an integral part of the metering rod. In operative assembly, thecontrol end of the metering rod is not self-retained in contact with oneside of the jet orifice, as in the primary embodiments, but is so heldby a light spring 16 having a hook-end l8 seated against the meteringrod. Spring '16 is carried on member 10 in tensioned condition, byprojection of its opposite end 19 through a transverse passage 80provided in member 10, with the terminal portion 82 hooked over themember, as shown.

It will be understood, of course, that the several embodiments of theinvention, as herein shown and' dle scribed, may be altered or modifiedwithout departing from the spirit and full intended scope of theinvention as defined by the appended claim.

In a carburetor provided with a liquid fuel supply passagevv ay having arestricted orifice therein, a longitudinally movable metering rod havinga control end portion movablethrough said restricted office for variablyrestricting fuel flow therethrfo h, said rod terminating at its oppositehaped portion of substantially uni- I I r, and a metering rod operatingmember having a rod attaching lug with an opening therethrough of adiameter substantially greater than the diameter of said crank portion,said openinghaving its axisiat a right angle to the direction ofmovement of said rod, and said rod crank portion having its intermediatetransverse part disposed at a different angle to said direo- REFERENCESCITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,605,417 Willoughby Nov. 2, 19261,961,747 Ewart June 5, 1934 2,394,663 Carlson et a1 Feb. 12, 19462,407,535 Carlson et a1 Sept. 10, 1946

